I’m scratching my head over this one… I have a dedicated circuit supplying an outdoor lamp post with an eye so it comes on at dark and shuts down at sunrise. I replaced the eye exactly as the old one came out. Red to red, black to black, white to white. Nothing tough about it. But whenever I throw the breaker to turn the circuit on, it and the breaker next to it are blown. I removed the panel cover and neither breaker has any shared conductors. Any of you sparkies ever run into this and what the dickens could be causing it?
Discussion Forum
Discussion Forum
Up Next
Video Shorts
Featured Story
Tips for protecting your personal information when using Wi-Fi-connected devices.
Featured Video
Highlights
"I have learned so much thanks to the searchable articles on the FHB website. I can confidently say that I expect to be a life-long subscriber." - M.K.
Replies
I'd say there's a connection somewhere.
Time to get a circuit checker of some sort and buzz it out. You need an ohmmeter or some sort of continuity tester.
Was there an outlet on this lamp post?
No, I traced every wire from the panel to the junction box to the eye box to the lamp including taking off the inspection plate from the lamp base and re working the connections in all the aforementioned. My only real uncertainty is if there's a nick in the line somewhere underground and it's shorting out. But that wouldn't make a neighboring breaker kick off when I tried to turn the lamp's breaker on. It's just weird... Any ideas? I'm all ears...
Backfeed possible
Are the two circuits going to the same junction box or do they meet anywhere? It sounds like your backfeeding one circuit with the other causing both breakers to trip. Do the breakers hold when the other one is off? If so, check your splices.
Richie
troubleshooting
Remove the new photocell, disconnect the wiring from the fixture as well. Cap off the wires with wirenuts.
Power up the circuit. If the breaker holds (doesn't trip), the problem is a bad photocell, or maybe one of the splices you made installing it.
If the breaker trips with the photocell and fixture out of the circuit, disconnect the suply wire from the breaker. If the breaker holds when you close it, it's a fault or short in the wiring between the breaker and the lamp post. If the breaker trips when you close it, it's a bad breaker.
If the problem is in the wiring between the panel and the post, look first at the wiring between the ground and the top of the post where the fixture is. Sometimes handling the wires can cause a short or fault at a point where the insulation has worn off the wire(s), but there was no contact until the wires moved.
Another thought: you mis-wired the photocell or fixture. It happens. If the problem goes away when you disconnect the photocell and fixture, you could check the wires at the lamp post to make sure which is which, and try re-making the connections.
Worst case--you wind up pulling new wires into the conduit to the post. Well, worst case, is that you have to trench and lay conduit, or new UF cable.
Good luck.
What I would do is disconnect both circuits at the breakers. Verify that the breakers will reset with no load attached. (BTW, is either of these a GFCI breaker?) Also find and disconnect the two white wires corresponding to those circuits.
Then use an ohmmeter to check between the two black wires coming off the breakers. (They're disconnected now, right?) There should be infinite resistance between the two wires. There should be infinite resistance between the two corresponding white wires. There should be infinite resistance between any of the four wires and ground.
Somewhere one of the above "should bes" will be violated, so then you go another part of the circuit, disconnect wires, and try again. You can either work from one end or "divide and conquer" by splitting things in the middle to find which end has the problem.
You have a dead short. I heard you say junction box, so check there first. Make sure everything is wired up properly and no bare wire shows.